The present invention relates to methods and apparatus for averaging sub-samples in a graphics system.
The sophistication of the market for computer and video graphics and games has exploded over the last few years. The time when simple games such as “Pong” was a marketable product is far in the past. Today's garners and computer users expect realistic images, whether the images are of a football game, race track, or new home's interior. Accordingly, this appetite has focused designers' efforts to improving the graphics systems in computers and video game systems.
Increasing the realism of video requires using sophisticated anti-aliasing techniques to reduce artifacts. One method of reducing aliasing artifacts is to store several images at a slight offset from each other in memory. The images are stored as an array of binary words referred to as sub-samples, where corresponding locations in memory hold a set of sub-samples which match up with a pixel on the display. As an image of an object drawn on the display's screen it will be stored in these memory locations, and appears to the sets of sub-samples as a new image. When a source pixel first moves to a sub-sample storage location, it is combined with the existing sub-sample. The sub-samples are then filtered to produce pixels. This technique works well, but current implementations tend to be expensive. What is needed is an alternative which would reduce the cost of mitigating these artifacts.